Fingerprint impressing position guiding method and fingerprint identification system

ABSTRACT

A fingerprint identification system, which can reduce repetitions of erroneous fingerprint input operations, includes a fingerprint input sensor on which an individual to be identified places a finger, which reads a fingerprint from the finger; a processor which determines a center of the fingerprint which is read by the fingerprint input sensor and calculates a gap between a center of the fingerprint input sensor and the center of the fingerprint; and a guiding unit which notifies a move direction to the individual based upon the gap and guides the finger to a proper position.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a fingerprint identificationsystem, more specifically, to a technique capable of preventingrepetitions of erroneous fingerprint input operation in such afingerprint identification system.

[0002] Nowadays, “security” problems are considered in various fields.In initial stages for securing such a “security” aspect, there is aproblem as to how to eliminate an individual who has no access right,and how to allow access operation by only an individual who owns accessright. To solve this problem, various sorts of individual identifyingmethods have been proposed. Among these identifying methods, fingerprintidentification systems are being considered as the individualidentifying method that is most effective and has the highestreliability.

[0003] While using such a feature of fingerprints that none of peoplecan have the same fingerprint pattern as another, fingerprintidentification systems may electronically read out fingerprints so as tospecify previously-registered individuals. In most of the fingerprintidentification system, when an individual to be identified puts his/herfinger on an input sensor for judging a fingerprint, a fingerprint ofthis finger is electronically read, and a check is made whether or notthis read fingerprint is made coincident with fingerprint data which hasbeen previously registered. As a result, these fingerprintidentification systems confirm whether or not the individual to beidentified corresponds to the identified individual.

[0004] However, although these fingerprint identification systems mayhave superior characteristics as the individual identifying method,there is such a risk that the fingerprint identification systems may notalways surely recognize such identified individuals who have beenpreviously registered in these identification systems. In a certaincase, even if a fingerprint of an individual to be identified has beensurely previously registered, such a fingerprint identification systemmay judge that there is no identified individual. This problem is mostprobably caused by a so-called “erroneous fingerprint input operation,”in which a finger of an individual to be identified is placed on aposition of an input sensor, which is shifted from a center portion ofthe input sensor.

[0005] As conventional systems capable of avoiding, or reducing such an“erroneous fingerprint input operation,” Japanese Patent ApplicationLaid-open No. Sho 62-170230 discloses the system (will be referred to as“prior art 1” hereinafter) and Japanese Patent Application Laid-open No.Hei 3-226888 discloses the system (will be referred to as “prior art 2”hereinafter). The prior art 1 opens such a system that while the contourlines corresponding to several sorts of finger sizes are displayed bythe input means, since the individual to be identified puts the fingeron the input means in such a manner that the finger size of thisindividual is fitted to the relevant contour line, the positional shiftbetween the finger position during the registration and the fingerposition during the identification can be reduced.

[0006] Meanwhile, the prior art 2 discloses such a system that thefinger tip holding unit employed in the finger guide is provided in sucha manner that either at least a portion or an entire portion of thefingerprint impressing plane may be surrounded. Also, in accordance withthe prior art 2, the positional shift can be prevented by such a mannerthat while the individual to be identified inserts the finger along thefinger guide, the finger tip portion of this individual to be identifiedis held by the finger tip holding unit so as to restrict the position ofthis finger tip portion.

[0007] However, even when the above-explained systems disclosed in theprior art 1 and the prior art 2 are conducted, these conventionalsystems cannot avoid occurrences of-such an “erroneous fingerprint inputoperation,” and thus, may most probably judge that there is noidentified individual. This is because there are many numbers of fingersizes different from each other, and also, individual to be identifieddo not always placed on their fingers on input sensors under suchdesirable conditions made by system designers.

[0008] Moreover, since these systems described in the prior art 1 andthe prior art 2 do not consider such cases, the individual to beidentified cannot apparently grasp how the finger putting position isshifted, but also cannot know whether or not the finger putting positionis positionally shifted in accordance with these conventional systems.As a consequence, there are some possibilities that the erroneousfingerprint input operation is repeatedly carried out.

SUMMARY OF THE INVENTION

[0009] Thus, the present invention has an object to provide a guidingmethod of a fingerprint impressing position, and a fingerprintidentification system using this guiding method of the fingerprintimpressing position, which may reduce repetitions of erroneousfingerprint input operations.

[0010] The Inventors of the present invention considered that, asdescribed above, the problems contained in the conventional systems maybe caused by such a point that after the judgement is made of “noidentified individual,” the fingerprint identification system does notnotify to the individual to be identified, such a fact whether or notthe fingerprint impressing position is incorrect with respect to thefingerprint input sensor. In accordance with the conventionalfingerprint identification system, when the judgement is made of “noidentified individual,” the individual to be identified cannot recognizewhether or not the position of the finger placed on the input sensor issuch a proper finger putting position. Also, when the judgement is madeof “no identified individual,” the individual to be identified willretry to put his/her finger on the input sensor in order to identify theindividual himself/herself. However, due to the samepreviously-explained reason, there are many possibilities that theindividual to be identified repeatedly performs the same erroneousfingerprint input operation.

[0011] The present invention has been made to consider this point, andtherefore, is featured by that when a judgement is made that no relevantindividual is present as a result of fingerprint identification, acalculation is carried out as to how degree a positional coordinatevalue of a finger placed on a fingerprint input sensor is shifted from acenter portion of the sensor, and then, proper guidance information isoutputted to an external output apparatus. As a consequence, anindividual to be identified can explicitly grasp “erroneous fingerprintinput operation,” and can put the finger more properly with respect tothe finger input sensor fingerprint impressing position when theindividual again puts the finger on the finger input sensor.

[0012] According to the present invention, a guiding method of afingerprint impressing position for guiding a finger placed on afingerprint input sensor by an individual to be identified to a properfingerprint impressing position in a fingerprint identification system,includes: a step of reading a fingerprint from the finger placed on thefingerprint input sensor; a step of determining a center of thefingerprint which is acquired by the fingerprint input sensor; a step ofcalculating a gap between a center of the fingerprint input sensor andthe center of the fingerprint; and a step of notifying a move directionof the finger to the individual based upon the gap.

[0013] According to the present invention, a fingerprint identificationsystem includes: a fingerprint input sensor on which an individual to beidentified places a finger, which reads a fingerprint from the finger; aprocessor which determines a center of the fingerprint which is read bythe fingerprint input sensor and calculates a gap between a center ofthe fingerprint input sensor and the center of the fingerprint; and aguiding unit which notifies a move direction to the individual basedupon the gap and guides the finger to a proper position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] These and other objects, features and advantages of the inventionwill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings, in which:

[0015]FIG. 1 is a schematic diagram for showing an arrangement of afingerprint identification system according to a first embodiment modeof the present invention;

[0016]FIG. 2 is a flow chart for describing operations of thefingerprint identification system indicated in FIG. 1.

[0017]FIG. 3 is a flow chart for explaining a method of guiding afingerprint impressing position in the fingerprint identification systemshown in FIG. 1;

[0018] FIGS. 4(a) to 4(d) are a diagram for explaining a coordinatepositional relationship between a fingerprint input sensor and aninputted fingerprint (fingerprint data);

[0019]FIG. 5 is a schematic diagram for representing an arrangement of afingerprint identification system according to a second embodiment modeof the present invention; and

[0020]FIG. 6 is a schematic diagram for representing an arrangement of afingerprint identification system according to a third embodiment modeof the present invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Next, the present invention will be explained in detail below inreference to the accompanying drawings.

[0022] Referring to FIG. 1, a fingerprint identification system,according to a first embodiment of the present invention, includes aprocessor 10, a memory 20, an input/output interface (I/O) 30, and afingerprint identifying unit 40. The memory 20 stores thereinto aprogram for causing the processor 10 to execute a method of guiding afingerprint impressing position (will be discussed in detail later on)according to this embodiment.

[0023] The fingerprint identifying unit 40 includes a fingerprint inputsensor 41 and an LED indicator 42. An individual to be identified putshis/her finger on the fingerprint input sensor 41. Here, thepresently-available techniques such as a CCD and an electricalcapacitance type sensor may be applied to the fingerprint input sensor41. The LED indicator 42 guides a move direction of a finger to anindividual to be identified by displaying characters of “↓”, “↑”, “→”,and “←”

[0024] Next, referring to FIG. 2 to FIG. 4, operations of thefingerprint identification system according to this embodiment will beexplained, more specifically, a description is made of a method ofguiding a fingerprint impressing position in accordance with thisembodiment.

[0025] Referring to FIG. 2, when an individual to be identifiedpositions the own finger on the fingerprint input sensor 41 so as tocommence the fingerprint identification (step S1), the fingerprintidentification system electronically reads out a fingerprint from thefinger positioned on the fingerprint input sensor 41 (step S2).

[0026] Next, the processor 10 judges whether or not the fingerprintacquired by the fingerprint input sensor 41 (namely, fingerprint data)is made coincident with a previously registered fingerprint of aregistered individual (step S3). In the case that the processor 10judges “coincident (Yes),” the processor 10 accomplishes the fingerprintidentification processing operation, assuming that the fingerprintidentification is a success succeed (step S4). On the other hand, in thecase that the processor 10 judges “not coincident (No)” at the step S3,the processor 10 outputs guidance information with respect to the LEDindicator 42 (step S5), and is brought into a waiting state until theindividual to be identified moves his/her finger and the fingerprintacquiring operation is again carried out.

[0027] Here, the contents as to the step S5 will now be explained morein detail with reference to FIG. 3 and FIG. 4. First, an axis of thefingerprint input sensor 41 is previously determined as shown in FIG.4(a). Under this condition, the processor 10 determines an axis of thefingerprint and a center of the fingerprint (see FIG. 4(b)) which isacquired at the above-described step S2 (step S51).

[0028] Then, the processor 10 judges whether a gap between a center ofthe fingerprint input sensor 41 ((X, Y)=(0, 0): will be referred to X₀,Y₀) and a center of the fingerprint ((X, Y)=(x₀, y₀): will be referredto x₀, y₀) is large than a predetermined amount. FIG. 4(c) show thecenter of the fingerprint just corresponds to the center of thefingerprint input sensor 41. FIG. 4(d) shows that the gap is large thanthe predetermined amount. Here, the predetermined amount corresponds toan allowable shift amount.

[0029] In this case, as shown in FIG. 4(a), in the fingerprintidentification system according to this embodiment, the fingerprintinput sensor 41 is defined as such a range of “−150≦Y<150, −150≦X<150,”and it is assumed that a range defined by “−50≦Y<50, −50≦X<50” is usedas an effective range. In other words, in this embodiment, there is noerroneous fingerprint input operation as long as the center of thefingerprint is entered within this range of “−50≦Y<50, −50≦X 50.” As aconsequence, the allowable shift amount is defined by “−50≦y₀<50,−50≦x₀<50” in this embodiment.

[0030] In particular, in accordance with this embodiment, the gap isseparately judged with respect to each of the upper/lower/right/leftdirections on the fingerprint input sensors 41. Concretely speaking, theprocessor 10 first judges whether or not the center of the fingerprintmeets a condition, “y₀<−50” (step S52). As a result of this judgement,in the case that the center of the fingerprint meets the condition“y₀<−50,” the processor 10 instructs the LED indicator 42 to displaythereon such an indication “↑” in order to guide the fingerprintimpressing position along the upper direction (step S53). In the casethat the center of the fingerprint meets a condition, “y₀≧−50,”subsequently, the processor 10 judges whether or not the center of thefingerprint meets a condition, “y₀≧50” (step S54). As a result of thejudgement performed at the step S54, in the case that the center of thefingerprint meets the condition, “y₀≧50,” the processor 10 instructs theLED indicator 42 to display thereon such an indication “↓” in order toguide the fingerprint impressing position along the lower direction(step S55). In the case that the center of the fingerprint meets acondition, “y₀<50,” subsequently, the processor 10 judges whether or notthe center of the fingerprint meets a condition, “x₀<−50” (step S56). Asa result of the judgement performed at the step S56, in the case thatthe center of the fingerprint meets the condition, “x₀<−50,” theprocessor 10 instructs the LED indicator 42 to display thereon such anindication “→” in order to guide the fingerprint impressing positionalong the right direction (step S57). In the case that the center of thefingerprint meets a condition, “x₀≧−50,” subsequently, the processor 10judges whether or not the center of the fingerprint meets a condition,“x₀≧50” (step S58). As a result of the judgement performed at the stepS58, in the case that the center of the fingerprint meets the condition,“x₀≧50,” the processor 10 instructs the LED indicator 42 to displaythereon such an indication “←” in order to guide the fingerprintimpressing position along the left direction (step S59).

[0031] Assuming now that as a result of the judgement made at the stepS58, the center of the fingerprint meets a condition, “x₀<50,” sincethis case implies that the fingerprint impressing position need not beguided, no guidance is carried out, and the identification processoperation is returned to the step S2 in FIG. 2. At this step S2, thefingerprint acquisition operation is again carried out. The case inwhich the judgement is made of “No” at the step S58 is given as follows:That is, for example, the individual to be identified does not puthis/her finger on the fingerprint input sensor 41; the fingerprint dataof the individual to be identified is made coincident with thepreviously-registered fingerprint data; and although the fingerprintdata of the-individual to be identified is not made coincident with thepreviously-registered fingerprint data, the center of the fingerprint ispresent within the previously-indicated effective range.

[0032] Since such an arrangement is employed, in accordance with thisembodiment, even when the erroneous fingerprint input operation iscarried out in the fingerprint identification, the correction direction(namely, move direction of finger) of the fingerprint impressingposition can be notified by the LED indicator 42 with respect to theindividual to be identified while the subsequent fingerprintidentification is carried out. As a result, since the individual to beidentified can visibly recognize the move direction of the finger, therepetition of the erroneous fingerprint input operation can be reduced.

[0033] In the above-described embodiment, such a judgement that thefingerprint impressing position can be inputted to the proper inputposition with respect to the fingerprint input sensor may be made in thecase where the center of the fingerprint is located within the effectiverange of “−50≦y₀<50, −50≦x₀<50.” This reason is given as follows: In thecase where a total number of effective pixels of the fingerprint inputsensor 41 is expressed as “−150≦Y<150, −150≦X<150,” ⅓ of these totaleffective pixel numbers along the respective directions are employed asapproximated values. Assuming now that this approximated value isselected to be ¼ of these total effective pixel numbers, a narrowereffective range may be set. Also, assuming now that this approximatedvalue is selected to be ⅖ of these total effective pixel numbers, awider effective range may be set.

[0034] Also, in the above-explained embodiment, the gap between a centerof the fingerprint input sensor 41 and a center of the fingerprint aresequentially evaluated along the minus direction of the Y axis, the plusdirection of the Y axis, the minus direction of the X axis, and the plusdirection of the X axis. Alternatively, these evaluation orders may bereplaced. Furthermore, alternatively, the guidance information of thefingerprint impressing position may be outputted to the indicator withrespect to such a direction having a maximum amount of a gap.

[0035] Next, a second embodiment of the present invention will beexplained below. A fingerprint identification system according to thesecond embodiment of the present invention corresponds to a modificationof the above-explained fingerprint identification system according tothe first embodiment, and owns the same constructions as those of thefingerprint identification system according to the first embodimentmode, except for such a technical point that a fingerprint identifyingunit 44 indicated in FIG. 5 is employed instead of the fingerprintidentifying unit 40 shown in FIG. 1.

[0036] Referring to FIG. 5, the fingerprint identifying unit 44 includesa fingerprint input sensor 41, and 4 sets of LED indicators 45 which areprovided in such a manner that these LED indicators are located tosurround this fingerprint input sensor 41 from four positions. Thesefour LED indicators 45 are employed in order to indicate a movedirection of a finger to an individual to be identified in accordancewith a method of guiding a fingerprint impressing position according tothis embodiment. These LED indicators 45 are arranged in such a mannerthat such an LED indicator 45 corresponding to a finger move directionis turned ON.

[0037] Operations of such a fingerprint identification system areidentical to the operations of the fingerprint identification systemaccording to the first embodiment, which have been explained byemploying FIG. 2 to FIG. 4, except for the below-mentioned points. Inother words, in the fingerprint identification system according to thisembodiment, at the respective steps S53, S55, S57 and S59 shown in FIG.3, the processor 10 turns ON the “upper” LED indicator 45, the“lower”LED indicator 45, the “right” LED indicator 45, and the “left”LEDindicator 45, corresponding to the “upper”, “lower”, “right”, and “left”directions, in order that the fingerprint impressing w position isguided to the “upper”, “lower”, “right”, and “left” directions,respectively.

[0038] Since such an arrangement is employed, in accordance with thisembodiment, even when the erroneous fingerprint input operation iscarried out in the fingerprint identification, the correction direction(namely, move direction of finger) of the fingerprint impressingposition can be notified by the LED indicator 45 with respect to theindividual to be identified while the subsequent fingerprintidentification is carried out. As a result, since the individual to beidentified can visibly recognize the move direction of the finger, therepetition of the erroneous fingerprint input operation can be reduced.

[0039] It should also be noted the various sorts of modificationsdescribed in the explanations related to the fingerprint identificationsystem according to the first embodiment may be applied also to thefingerprint identification system according to this embodiment mode.

[0040] Next, a third embodiment of the present invention will beexplained below. A fingerprint identification system according to thethird embodiment of the present invention corresponds to a modificationof the above-explained fingerprint identification system according tothe first embodiment, and owns the same constructions as those of thefingerprint identification system according to the first embodiment,except for such a technical point that a fingerprint identifying unit 47indicated in FIG. 6 is employed instead of the fingerprint identifyingunit 40 shown in FIG. 1.

[0041] Referring to FIG. 6, the fingerprint identifying unit 47 includesa fingerprint input sensor 41, and a speaker 48 which is provided in thevicinity of this fingerprint input sensor 41. This speaker 48 is used soas to indicate a move direction of a finger by voice to an individual tobe identified in accordance with a method of guiding a fingerprintimpressing position according to this embodiment.

[0042] Operations of such a fingerprint identification system areidentical to the operations of the fingerprint identification systemaccording to the first embodiment, which have been explained byemploying FIG. 2 to FIG. 4, except for the below-mentioned points. Inother words, in the fingerprint identification system according to thisembodiment, at the respective steps S53, S55, S57 and S59 shown in FIG.2, the processor 10 transfers instructions to the individual to beidentified via the speaker 48 by way of voice in order that thefingerprint impressing position is guided to the “upper”, “lower”,“right”, and “left” directions, respectively.

[0043] Since such an arrangement is employed, in accordance with thisembodiment mode, even when the erroneous fingerprint input operation iscarried out in the fingerprint identification, the correction direction(namely, move direction of finger) of the fingerprint impressingposition can be notified by the speaker 48 with respect to theindividual to be identified while the subsequent fingerprintidentification is carried out. As a result, since the individual to beidentified can audibly recognize the move direction of the finger, therepetition of the erroneous fingerprint input operation can be reduced.

[0044] It should also be noted the various sorts of modificationsdescribed in the explanations related to the fingerprint identificationsystem according to the first embodiment may be applied also to thefingerprint identification system according to this embodiment.

[0045] In accordance with the present invention, when the erroneousfingerprint input operation to the fingerprint input sensor causes thefailure in the fingerprint identification, since the concreteinstruction capable of guiding the fingerprint impressing position isnotified to the individual to be identified, possibility of succeedingin the subsequent fingerprint identification becomes extremely high.

[0046] Also, in accordance with the present invention, every time theindividual to be identified mistakenly puts his/her finger on thefingerprint input sensor, this individual can recognize the deviationdegree of the fingerprint impressing position. As a result, it can beexpected that every time the individual to be identified repeats such anerroneous fingerprint input operation, this individual can learn it byhimself/herself and can master the correct fingerprint input operation.As a consequence, it may be possible to reduce workloads which arerequired to notify a correct fingerprint inputting method of thefingerprint input sensor in detail to the individual to be identified,for example, just after the fingerprint identification system isintroduced.

[0047] Moreover, in accordance with the present invention, while payingattention to such a fact that the information amount for guiding thefingerprint impressing position is limited, the LED indicators areemployed as the transfer means of the guidance information without usingsuch as an expensive display unit as an LCD. As a result, the productioncost of the fingerprint identification system can be suppressed.

[0048] While this invention has been described in conjunction with thepreferred embodiment described above, it will now be possible for thoseskilled in the art to put this invention into practice in various othermanners.

What is claimed is:
 1. A guiding method of a fingerprint impressingposition for guiding a finger placed on a fingerprint input sensor by anindividual to be identified to a proper fingerprint impressing positionin a fingerprint identification system, comprising: a step of reading afingerprint from the finger placed on said fingerprint input sensor; astep of determining a center of said fingerprint which is acquired bysaid fingerprint input sensor; a step of calculating a gap between acenter of said fingerprint input sensor and said center of saidfingerprint; and a step of notifying a move direction of the finger tosaid individual based upon said gap.
 2. The guiding method of afingerprint impressing position as claimed in claim 1, wherein thenotification of the move direction of the finger with respect to saidindividual to be identified is carried out in such a manner that saidfinger move direction is displayed as an arrow with respect to adot-displayable indicator provided in said fingerprint identificationsystem.
 3. The guiding method of a fingerprint impressing position asclaimed in claim 1, wherein the notification of the move direction ofthe finger with respect to said individual to be identified is carriedout in such a manner that among four indicators which are provided atfour surrounding positions of said fingerprint input sensor in saidfingerprint identification system, any one of the indicators, whichcorresponds to said finger move direction, is turned ON.
 4. The guidingmethod of a fingerprint impressing position as claimed in claim 1,wherein the notification of the move direction of the finger withrespect to said individual to be identified is carried out in such amanner that said finger move direction is transferred by voice to saidindividual to be identified via a speaker provided in said fingerprintidentification system.
 5. A fingerprint identification systemcomprising: a fingerprint input sensor on which an individual to beidentified places a finger, which reads a fingerprint from said finger;a processor which determines a center of said fingerprint which is readby said fingerprint input sensor and calculates a gap between a centerof said fingerprint input sensor and said center of said fingerprint;and a guiding unit which notifies a move direction to said individualbased upon said gap and guides the finger to a proper position.
 6. Thefingerprint identification system as claimed in claim 5, wherein saidguiding unit comprises a dot-displayable indicator and displays saidmove direction as an arrow.
 7. The fingerprint identification system asclaimed in claim 5, wherein said guiding unit comprises four indicatorsprovided at four surrounding positions of said fingerprint input sensor,one of said indicators corresponding to said move direction being turnedON.
 8. The fingerprint identification system as claimed in claim 5,wherein said guiding unit comprises a speaker which guides said movedirection by voice.